The idea of empathy for all ignores the limits of human psychology. "Our instinctive tendency to categorize the world into “us” and “them” is difficult to overcome. It is in our nature to favor helping in-group members like friends, family, or fellow citizens, and to neglect or even punish out-group members. Even as some moral circles expand, others remain stubbornly fixed, or even contract: Just think of Democrats and Republicans, Sunnis and Shiites, Duke and North Carolina basketball fans."











